Part 2 Kawasaki STX-15F Detailed Engine Rebuild

[@TheStephenspann27]

I really appreciate the detailed video. It's been nearly two years since I took my engine apart so this will be helpful

[@rowlandrestorations]

Thanks! Good luck!

[@geraldjones4126]

Thank you!! Your time is greatly appreciated!

[@rowlandrestorations]

Thank you! Glad I can help!

[@marcog3210]

Love the video! Been waiting on it thought it was never gonna come. Congratz on the ski!

[@rowlandrestorations]

Took longer than I expected haha. Thanks!

[@paulbaker7015]

Amazing video mate - would love to stay that organised when filming, makes great content well done 👍

[@rowlandrestorations]

I appreciate that! Thanks!

[@marczhp1766]

If doing this should I get the head and cylinder jug shave? Great video btw

[@rowlandrestorations]

@@marczhp1766 If you have a machine shop that will deck your cylinder head and deck your cylinder, absolutely! It’ll be the best way to get the best sealing surface between the two. But you can check it with a straight edge if you have one and see if they need it. Machine shop can check them for you too

[@marczhp1766]

@@rowlandrestorations thanks for the reply

[@outdoorAllard]

Just finished helping a buddy replace the head on his 2006 STx-12F, this video was helpful for timing. We have 1 hose coming off the bottom of the water box that we cannot for the life of us figure out where its supposed to connect to... any ideas? Used camera phone to look under intake / exahust but dont see any open ports...

[@rowlandrestorations]

Glad to hear it! That sounds like it might be the hose coming off of the cylinder head. It is right under the intake manifold. I have the service manual linked in the description. Look on page 254 at the exploded view of the cooling system. Hopefully that will help you make sense of it. The 12F intake manifold is a little different but the cylinder heads are exactly the same

[@outdoorAllard]

@@rowlandrestorations thanks. I’ll have a look at the manual. The hose seemed to come short of getting all the way under the intake manifold…

[@outdoorAllard]

Looking at the manual I believe the head we purchased did not come with the head cooling pipe that it connects to and the core we sent back had it on it....

[@rowlandrestorations]

@@outdoorAllard Damn! That sucks. Well It could have been rotted out anyway so might as well get a new one. I ordered mine from Jetstar in Japan. I received it less than a week and was half the price of any US supplier. The only downside is shipping can be pricy, so weigh your options and see if you need to order anything else. The OEM parts from there are SIGNIFICANTLY cheaper jetskiparts.jp/products/32144-3709?_pos=1&_psq=KAWASAKI+OEM+PIPE+%7C+32144-3709&_ss=e&_v=1.0

[@n.b.p.davenport7066]

Have fun good luck

[@krisztianmicsko3790]

Great video Did you reuse the old head bolts or did you get new ones?

[@rowlandrestorations]

Thanks! I reused them as well. After about 3 uses I would toss them but this was its first rebuild so I had no worries about using them

[@tgrip352]

Need you to rebuild mine! 😂

[@brokengaming4906]

After almost a full summer, how is the engine doing?

[@rowlandrestorations]

@@brokengaming4906 Runs amazing! I don’t ride it as much as my Yamaha but it runs flawlessly. Probably only put about 20-25 hours in it so far. I abuse it hard too

[@daiverst5120]

Could you please also tell torque values? thanks!

[@rowlandrestorations]

I will do that in the future! What torque values do you need?

[@dproulx7380]

i have dumb question where does the second hose from oil pan connect too

[@rowlandrestorations]

No worries! It connects to the bottom of the catch can. It allows the oil vapors collected in the catch can to drain back down to the oil pan

[@dproulx7380]

@@rowlandrestorations i will have more stupid questions on my install thanks for responding

[@rowlandrestorations]

@@dproulx7380 No worries! Happy to help!

[@douglasweeks7407]

Hi, like your videos, question, i going to install the exhaust manifold gasket, but i am not 100% with way our witch side goes to the engine our with side goes to the manifold Hope you can help me. Thank you

[@rowlandrestorations]

Thanks! You can install it either way. It doesn't matter. Good luck wrenching!

[@douglasweeks7407]

Thank you very much.

[@vikp7885]

What is the torque pounds on the cylinder head bolts?

[@rowlandrestorations]

43 ft/lbs final on the bigger bolts, 14 ft/lbs on the smaller ones. Do it at least in 2 stages

[@vikp7885]

@@rowlandrestorations Thanks, I am fixing my 2014 kawasaki ultra 310x , the engines looks the same , should be the same torque I think

[@rowlandrestorations]

@@vikp7885 They are very similar but with the boost yours has it has a slightly higher torque spec. Final torque is 52 ft/lbs

[@vikp7885]

@@rowlandrestorations Ok, thanks for let me know

[@rowlandrestorations]

@@vikp7885 For sure. Good luck

[@Xllinemarking]

how did you know what size and colour crank bearings to buy??

[@rowlandrestorations]

Great question! If you know the crankshaft hasn't been ground / resized, then go with standard (STD) bearings. To be certain, you can measure the crankshaft journal diameter and compare it with the manual. Page 8-4 and 8-5. I attached a link to the manual if you need it. Hope this helps! www.dropbox.com/scl/fi/e5rpmgbaw1ea9qcbq1fsw/STX-15F-service-manual.pdf?rlkey=2l0hf045bil73j4okmy6z0szd&dl=0

[@robbiesmith1334]

How many lb/ft on head bolts and the camshaft cap??

[@rowlandrestorations]

Head bolts need at least 2 torque passes. First is 17 ft/lbs, then 43 ft/lbs final. Camshaft cap is about 9 ft/lbs or 104 in-lbs. Its on page 181 in the service manual. www.dropbox.com/scl/fi/e5rpmgbaw1ea9qcbq1fsw/STX-15F-service-manual.pdf?rlkey=2l0hf045bil73j4okmy6z0szd&e=1&dl=0

[@n.b.p.davenport7066]

New valve springs?

[@rowlandrestorations]

Same used ones

[@Jetskiservices]

did you really replace the rod bolts? I've always wondered if you could get by without replacing them. Never tried it though

[@rowlandrestorations]

Lol, sorry it wasn’t clear in the video, I did NOT replace them. It’s running fine. There a tools to measure the stretch of the bolts so it would be interesting to see how much some used ones are stretched over new ones. I really wasn’t worried about it. If you were to follow the factory’s recommendation on every single part, they’d have you throw out almost everything during rebuilds and the cost would be almost as much as an entire new ski

[@n.b.p.davenport7066]

That's a new crankshaft?

[@rowlandrestorations]

Nope. Same one

[@smiddy19801]

Does one of the exhaust port nt have a big hole in it?

[@rowlandrestorations]

Great questions! So that extra hole you see in the exhaust ports is a passage to the Reed valves in the valve cover. It was Kawasaki's way of emissions control using secondary air injection in the exhaust. It has no bearing on performance or anything and the later cylinder heads (maybe 2008-newer) blocked those ports and removed the ports in the valve covers. Hope this answers your question!

[@bryannelson7317]

Hello, can you tell me where you picked up the rotor tool? Thanks

[@rowlandrestorations]

Search “rotor holder 57001-1544”. I bought a used one off eBay, but I think Partzilla might be able to get them. They most likely will order it from a Kawasaki dealer

[@TheStephenspann27]

did you happen to take the exhaust stinger off the collector at the manifold? There is a cone in that that frequently rots out and it can cause engine failure.

[@rowlandrestorations]

The stinger where it goes into the waterbox definitely had a few holes. I didn't film that part but I did braze in some aluminum alloy filler to seal it up. That is still holding fine but it's on my mind to replace it at some point. But as long as its not leaking then I'm going to run it. Great input! The exhaust is highly prone to rotting out

[@TheStephenspann27]

@@rowlandrestorations I'm talking about on the manifold side, if you take the bolts off and pull the stinger off the collector, there is a cone inside. I have a video on my channel about it.

[@TheStephenspann27]

kzbin.info/www/bejne/l6CUdmqAba55rdE&ab_channel=TheStephenspann27@@rowlandrestorations

[@rowlandrestorations]

@@TheStephenspann27 I checked out your video (stx15f, 12f exhaust). The part where the exhaust rings (piston ring type things) seal against that stainless steel sleeve inside the waterbox…. Ya that was definitely all rotted out on mine. I probably should’ve used JB weld like you but I brazed in some aluminum to seal it. It’ll be something I probably replace in the future if I start noticing more water in the hull

[@n.b.p.davenport7066]

You need to check oil clearances?

[@rowlandrestorations]

Could have but didn’t. Didn’t even really need to replace any of the bearings but I replaced them with standard size ones anyway cuz I was in there

[@rowlandrestorations]

To expand on this, the crankshaft was not damaged in any way so I could just use standard bearings. I only needed to verify they were the correct standard size and not oversized like if you were to get the crankshaft machined down. Once you start getting away from factory sizes by machining surfaces, crankshaft, center bores, etc, then you'll need to be more careful about measuring. This kawasaki engine is well designed so you can get away with a lot which is one of the points I tried to show

[@smiddy19801]

Hey mate, did you have any issue with re-using the rod bolts?

[@smiddy19801]

It cool i just read one of your other comments 🙂

[@rowlandrestorations]

Yup! I would just say inspect them closely and make sure there is no visible taper to them. The costs add up quick when rebuilding, so I say reuse where you can!

[@Millennial1031]

Whats your max mph after that refresh? Trying to see if a refresh is due myself - I'm hitting 60 gps in perfect conditions.

[@rowlandrestorations]

@@Millennial1031 I haven’t gotten a great read yet. My best GPS run on it so far is 60.0mph but it was choppy and I know for certain my jet pump impeller clearance isn’t perfect. If you’re hitting 60, I would say that’s right on for a stock machine. You might be able to get more with a single water box and removing the air box. I would say enjoy it. You can do a compression test and see how those numbers look but I would say you’ve got a healthy ski

[@Millennial1031]

@@rowlandrestorations tried 3 different testers and I’m at about 120 which is low, but ski feels good.

[@rowlandrestorations]

@@Millennial1031 Hmm, I would say that is low. Are you testing it after running it so there's heat in it? Are you holding the throttle wide open when cranking? Those will drastically affect the numbers. If you're hitting 60 I would say that's pretty good. And even if the numbers are showing low, if they are all close to each other (

[@Millennial1031]

@@rowlandrestorationsI had a bad piston. I’m not sure how it ran the way it did, because soon as I pulled the head off there was a piece missing on the skirt and the compression ring was visible on #4. I installed 12f pistons to increase compression. 250 psi, running 93 + a can of VP octane boost to be safe and I’m hitting 62. I also installed a kspeed ride plate but it didn’t give me any extra speed

[@rowlandrestorations]

@@Millennial1031 THAT IS AWESOME! I didn't think the 12F pistons would have the clearance but that is good to know. I think I will try that on another build now... Did you modify the timing plate or do any tuning? Or is it just stock with the higher compression?

[@heidilinnea313]

promo sm 🙋